Method of fabricating multiple-ply bellows

ABSTRACT

In the fabrication of a bellows having concentric radially spaced inner and outer plies from a bellows having concentric inner, intermediate, and outer plies, the plies are sectioned into longitudinal sections, the sections of the intermediate ply are removed from between the sections of the inner and outer plies, and the sections of the inner and outer plies respectively are welded together to reform the inner and outer plies.

United States Patent 11 1 11 1 3,800,398 Harrington, Jr. Apr. 2, 1974METHOD OF FABRICATING 3,550,253 12/1970 Fl'Cy 29/4711 MULTIPLE-FLYBELLOWS [76] Inventor: Edward F. Harrington, Jr., 2154 PrimaryExaminer-Richard B. Lazarus Emerson Ave., Louisville, Ky. Attorney,Agent, or Firm-N. M. Esser 40205 1 1221 Filed: Dec. 14, 1972 [57]AB'QTRACT 211 Appl. No; 315,259

In the fabrication ofa bellows having concentric radially spaced innerand outerplies from a bellows hav [52] Cl g/ igg g ifi ing concentricinner, intermediate, and outer plies, the 51 I t plies are sectionedinto longitudinal sections, the sec- E J 426 tions of the intermediateply are removed from bele 0 earc tween the sections of vthe inner andouter plies, and the sections of the inner and outer plies respectivelyReferences Cited are welded together to reform the inner and outer lies.UNITED STATES PATENTS p 2,797,112 6/1957 Ziebold 29/454 x 4 Claims, 5Drawing Figures BACKGROUND OF THE INVENTION This invention pertains to amultiple-ply bellows of the type in which the space between adjacentplies may be maintained at a controlled pressure and monitored to detectpressure change indicative of a leak in either ply. Prior examples ofsuch bellows are described in US. Pat. Nos. 2,125,447, 3,183,022,3,299,417, 3,472,062, and 3,655,224.

The above-mentioned patents describe various expedients to provideradial spacing between adjacent plies of a multiple-ply bellows. As oneexample, US. Pat. No. 3,183,022 describesa thin foil layer to beinserted between the plies to act as'a cushion and improve theresistance of the outer ply to breaks caused by mechanical action. Asanother example, US. Pat. No. 3,299,417 describes a two-ply bellowsinitially having an intermediate layer of a low-melting ductile alloy'to be caused to melt and flow out after the bellows has been formedwith suitable convolutions. Several examples of fluid-pervious meshworkto be employed as a permanent intermediate layer between adjacent pliesofa multiple-ply bellows are described in US. Pat. Nos. 2,125,447,3,299,417, and 3,655,224.

SUMMARY OF THE INVENTION One object of this invention is to provide anew and improved method of fabricating a bellows having concentricradially spaced inner and outer plies. Another object of this inventionis to provide a new and improved method offabricating such a bellowsfrom a bellows having concentric inner, intermediate, and outer plies.

Broadly, these objects may be attained by sectioning atleast one of theinner and outer plies into cylindrical sections, whereby the sectionsand the intermediate ply readily may be removed, removing theintermediate ply, and welding the sections together to reform the innerand outer plies. When suitably positioned, the inner and outer plies areradially spaced approximately by the thickness of the intermediate ply.

Preferably, the inner, intermediate, and outer plies are sectioned intocylindrical sections, whereupon, after the sections of the intermediateply are removed from between the sections of the inner and outer plies,the sections of the inner and outer plies respectively are weldedtogether to reform the inner and outer plies.

These and other objects, features, and advantages of this invention willbe evident from the following detailed description, with the aid of theaccompanying drawing, of a preferred mode of carrying out thisinvention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a longitudinal sectional view of a three-ply bellows fromwhich a bellows having concentric radially spaced inner and outer pliescan be fabricated;

FIG. 2 is a diametrical sectional view taken substantially along line 22of FIG. 1;

FIG. 3 is a view, analogous to FIG. 2, of a bellows having radiallyspaced inner and outer plies, as fabricated from the bellows of FIGS. 1and 2;

FIG. 4 is an enlarged fragmentary detail ofa seam of the bellows of FIG.3; and

FIG. 5 is a detail, analogous to FIG. 4, of a modification of thebellows of FIG. 3.

DETAILED DESCRIPTION OF PREFERRED MODE FIGS. I and 2 illustrate abellows I0 having concentric inner, intermediate, and outer plies, 12,14 and 16 respectively. Each ply of the bellows 10 comprises one or morecircumferential convolutions 18, two being shown between oppositetubular end portions 20 commonly called tangent ends.The convolutions 18of the respective plies are in radial registry and in closelyinterfitting nested relationship with each other. For the purposes ofthis invention, the bellows 10 may be formed, as from three concentricnested tubes, by any suitable hydraulic or mechanical means known to theart.

Preferably, the plies l2 and 16 are made of metal tubing. This inventioncontemplates the use of various materials including wire mesh, metaltubing, polyethylene sheeting or tubing, etc., for an intermediate ply.

For the purposes of this invention, the intermediate ply 14 is removedfrom between the inner ply l2 and the outer ply 16, after at least oneof the inner and outer plies has been sectioned into cylindricalsections. Preferably, the intermediate ply 14 is removed from betweenthe inner ply 12 and the outer ply 16 after the plies 12, I4, and 16 aresectioned, as by longitudinal cuts in the diametrical plane AA of FIG.2, into cylindrical halves, each half approximating 180 arc at oppositeends. Thus, the'halves of the intermediate ply l4 readilycan be removedfrom between corresponding halves of the inner and outer plies. For somepurposes contemplated by this invention, the plies l2, l4, and 16 may besectioned into longitudinal sections other than cylindrical halves, aswhere cylindrical quarters are to be used as comer pieces for agenerally rectangular bellows having generally planar convoluted sides.

After the removal of the intermediate ply 14 from between the inner ply12 and the outer ply l6, appropriate cylindrical sections are weldedtogether to reform these inner and outer plies. Where such removal hasbeen accomplished by sectioning the plies 12, 14, and 16 intocylindrical halves, the halves of the inner ply l2 initially are weldedtogether along longitudinal seams 22 (FIG. 3) to reform the inner plyl2, and the cylindrical halves of the outer ply l6 subsequently arewelded together along longitudinal seams 24 (FIG. 3) to reform the outerply 16.

As shown in FIG. 3, the seams 22 of the inner ply l2 and the seams 24 ofthe outer ply 16 may be displaced angularly, approximately as shown, toavoid any interference between welding beads at the respective seams 22and 24. As shown in FIGS. 3 and 4, similar strips 26 and 28 of asuitable backing material (cf. US. Pat. No. 2,916,001 may be applied tothe underside of the respective seams 22 and 24 to be welded. As shownin FIG. 5, a strip 30 of fluid pervious woven wire meshwork may beinserted between the inner ply 12 and the strip 28. The strip 30 assuresfree flow of monitored fluid across the seam 22 within the space betweenthe inner ply 12 and the outer ply 16.

When positioned in concentric relation to each other, the inner ply l2and the outer ply 16 thus are radially spaced approximately by thethickness of the intermediate ply l4. Annular spacers (not shown) ofcomparable thickness may be inserted between the inner ply 12 and theouter ply 16 at the respective tangent ends 20 to maintain such spacing.

The space between the inner ply l2 and outer ply 16 may be sealed, as bycircumferential weldments, at the respective tangent ends 20. Thus, asis known, such space may be maintained at a controlled pressure andmonitored to detect pressure change indicative of a leak in either ply.Suitable fittings and other apparatus for these purposes are describedin the abovementioned patents.

I claim:

1. A method of fabricating an elongated bellows having a longitudinalaxis and having concentric radially spaced inner and outer plies from abellows having concentric inner, intermediate, and outer pliescomprising the steps of sectioning at least one of said inner and outerplies into longitudinal sections, removing said intermediate ply frombetween said inner and outer plies,

respectively together to reform said inner and outer plies.

3. The method of claim 2 wherein said sections are cylindrical halves.

4. The method of claim 2 wherein said plies are sectioned along sectionlines disposed in radial planes.

1. A method of fabricating an elongated bellows havIng a longitudinalaxis and having concentric radially spaced inner and outer plies from abellows having concentric inner, intermediate, and outer pliescomprising the steps of sectioning at least one of said inner and outerplies into longitudinal sections, removing said intermediate ply frombetween said inner and outer plies, and welding said sections togetherto reform said inner and outer plies.
 2. A method of fabricating anelongated bellows having a longitudinal axis and having concentricradially spaced inner and outer plies from a bellows having concentricinner, intermediate, and outer plies comprising the steps of sectioningsaid plies into longitudinal sections, removing the sections of saidintermediate ply from between the sections of said inner and outerplies, and welding the sections of said inner and outer pliesrespectively together to reform said inner and outer plies.
 3. Themethod of claim 2 wherein said sections are cylindrical halves.
 4. Themethod of claim 2 wherein said plies are sectioned along section linesdisposed in radial planes.